"Car sales were really impressive," said Peter Cardillo, chief market economist at Rockwell Global Capital in New York. They're important for what they suggest about the larger economy: solid consumer spending and increased manufacturing. "It means the economy is holding up," Cardillo said.

Investors were also scrutinizing President Obama's effort to win support in Congress for a military strike on Syria.

The yield on the 10-year Treasury note edged up to 2.89% from 2.86% late Tuesday.

Jim Russell, a senior equity strategist at U.S. Bank Wealth Management in Cincinnati, said recent economic reports have drawn a brighter picture of the global economy, even as concerns over Syria have claimed much of the public's attention.

A Federal Reserve report on economic conditions in the 12 Fed bank districts said the economy continued to gain strength as all regions reported modest to moderate growth.

Shares of U.S. automakers rose as sales rose. General Motors said its sales rose 15% last month, while Chrysler and Ford each reported 12% gains. Toyota posted the biggest increase as sales rose nearly 23% since August of last year.

GM gained $1.71, or 5.0% to $35.85 and Ford jumped 57 cents, or 3.5%, to $16.91.

The Commerce Department reported that the trade gap grew 13% to $39.1 billion in July, thanks in part the rising price of crude oil and strong domestic demand for foreign autos and their parts. That comes after the trade deficit hit a four-year low in June.

The Nasdaq Stock Market said its quote dissemination system had a brief outage, from 11:35 a.m. to 11:41 a.m., but the problem was resolved and trading was not affected.

It was latest technical difficulty to hit the exchange. All trading in Nasdaq-listed stocks was halted for three hours on Aug. 22 because of a problem that was also blamed on the exchange's price quote disseminating system.

On Tuesday, stocks saw slight gains after a three-day holiday weekend and more upbeat economic indicators. A survey showed U.S. manufacturing grew at the fastest pace in more than two years in August as new orders rose.

The Dow rose 0.2% to close at 14,833.96. The S&P 500 gained 0.4% to close at 1,639.77. The Nasdaq gained 0.6% to 3,612.61.

Markets are weary as investors keep one eye on Syria developments. Members of the Senate Foreign Relations committee Tuesday drafted a resolution that would set a 60-day deadline for U.S. military action in Syria.

Japan's Nikkei 225 reversed early losses Wednesday and rose 75.43 points, 0.5%, to finish at 14,053.87. South Korea's Kospi ended down less than a point at 1,933.03. Hong Kong's Hang Seng also ended lower, down 68.36 points, or 0.3%, to end at 22,326.22.